Front Frame Rail Evaluation
Those TV car show guys that blast a car clean before work. yea it costs $and takes some time..but they have a reason!!! Me, IF I beat the crap out of suspect metal and try to drive a phillips in it, I have an idea! Any area not totally solid and clean when trying to mig will always have issues.
Make it safe like said and IF you will ever sell, make it clean and PRETTY!
I make my own frame connectors and add those to every car I will drive. If someone buys one of my cars and don't want them, he can cut them OUT!